Conventionally, a glass composition having (1) high refractive index (refractive index at the d line is from 1.88 to 2.20), (2) low softening temperature (490° C. or lower) and (3) small average thermal expansion coefficient (the average thermal expansion coefficient is (65 to 90)×10−7/K), and a member provided with the glass composition on a substrate (hereinafter referred to as “glass composition and the like) have not been present.
The glass composition and the like simultaneously provided with at most two requirements of the above three requirements are proposed (Patent Documents 1 to 5).
In recent years, environmental pollution becomes serious problem in the melting of a glass containing lead oxide. Therefore, the glass is required to not contain lead oxide.